Abstract
The southeastern part of the Solomon Islands, a highly seismically
active area in the southern Pacific, experienced two moderate
earthquakes (Mw 6.3 and 6.0) on January 27th and 29th, 2020. The
regional seismic network, operational since October 2018, recorded the
entire foreshock-main-shock-aftershock sequence, allowing for a new 1D
velocity model and relocation of events. Based on the spacial
distribution of the foreshock-aftershock sequence, together with focal
mechanism data from the Global CMT database, we suggest that there is a
near-vertical slab tear at the southern end of the South Solomon
subducting slab, abutting a zone of strike-slip faulting that links it
to the Vanuatu subduction zone to form a Subduction-Transform Edge
Propagator fault. Our new data also indicates that a seismic gap occurs
at depths from 25 to 35 km within the southern part of the South Solomon
slab.